An endoscope apparatus in which a treatment tool, such as a forceps arm, is attached in a protruded manner in front of an objective lens provided on a distal end surface of an insertion part has been conventionally known (for example, see PTL 1). With this endoscope apparatus, an image of an object, including the forceps arm, is acquired by the objective lens, and treatment is applied while observing the forceps arm and the object at the same time in the image.